[SR-Users] Missing ACK

[Claudio Furrer]

> > > > > > Hi, I have a similar issue,
> > > > > 
> > > > > It is not possible to debug this issue without full SIP trace!
> > > > > 
> > > > > ngrep -Wbyline -t -d any port 5060
> > > 
> > > I find it unpleasant to read such a trace. Please really use ngrep to get
> > > a
> > > nice formated SIP trace, or supply the pcap file.
> > > 
> > 
> > Ok, here it goes again.
> > 
> > Pay attention to the "200: OK" response from the PSTN-GW. I think its
> > Contact
> > header should be read by the Cisco GW (calling party), and then send its
> > ACK-request with R-URI based on that Contact. But it doesn't happen. Then
> > here i
> > think this is the failure. (rfc3261, section 12.1.1 and 12.2.1.2). May i am
> > wrong..
> > 
> > What do you think?
> > I'd appreciate your comments.
> 
> You are right. Caller behaves wrong, it should send ACK with
> RURI=ContactOf200Ok.
> 
> Maybe this is a buggy NAT traversal feature of Caller (Cisco?) which can be
> turned off.
> 
> If you can't fix it at Caller-side, you can make some workarounds at the proxy
> (if it is a fixed routing to the other gateway)
>

I think being a cisco device, there isn't too much to touch/modify. Just to 
start thinking about a workaround. Which kind of modification, source code or 
ser.cfg config? Maybe accepting and relaying all ACKs sent by this gw; simple, 
but insecure, not sure.

Thank you Klaus,
Caio